1. Field of the Invention
The present invention relates generally to a workpiece cutting method for use with a dicing machine, and more particularly to a workpiece cutting method for use with a dicing machine which cuts a semiconductor wafer into squares by using a pair of blades.
2. Description of Related Art
In a dicing machine disclosed in Japanese Patent Provisional Publication No. 8-25209, two spindles are arranged parallel to the Y-axis, and two blades attached to the two spindles cut a semiconductor wafer along cutting lines while the two spindles and the semiconductor wafer are moved relatively to one another along the X-axis. One of the two spindles is capable of adjusting the position along the Y-axis. The spindle is moved along the Y-axis by a predetermined amount to shift two blades by one pitch of the cutting lines, thereby cutting the semiconductor wafer along two cutting lines at the same time.
FIG. 9 is a transitional view describing the workpiece cutting method of the above-mentioned dicing machine. As shown in FIG. 9(A), two blades 1, 2 are positioned along the Y-axis at an interval of one pitch of the cutting lines on the wafer W. To cut the wafer W along the cutting lines L1 and L2, the blade 1 at the right side is aligned with the cutting line L1, and the two blades 1, 2 or the wafer W is moved along the X-axis so that the blade 1 can start cutting the wafer W along the cutting line L1 as shown in FIG. 9(B). Then, the blade 2 starts cutting the wafer W along the cutting line L2. The blades 1, 2 or the wafer W is moved until the blade 1 finishes cutting the wafer W along the cutting line L1 and the blade 2 finishes cutting the wafer W along the cutting line L2 as shown in FIG. 9(C). Consequently, the wafer W is cut along two cutting lines L1 and L2 at the same time. Reference numeral 3 is a motor for the blade 1, and 4 is a spindle of the motor 3. Reference numeral 5 is a motor for the blade 2, and 6 is a spindle of the motor 5.
According to the cutting method for the conventional dicing machine, however, the wafer W cannot be cut along two cutting lines L1 and L2 at the same time unless the blades 1, 2 are moved over a wide area E enclosed by broken lines D in FIG. 9(C), because two blades 1, 2 are arranged in parallel. This causes the blades 1, 2 to move unnecessarily, and therefore it takes a long time to cut the wafer W. Moreover, strokes must be long along the X-axis, and therefore, the dicing machine is too wide.
The present invention has been developed in view of the above-described circumstances, and has as its object the provision of a workpiece cutting method for use with a dicing machine, which decreases unnecessary movements of the blades to thereby reduce the cutting time.
To achieve the above-mentioned object, the present invention is directed to a workpiece cutting method in a dicing machine comprising the steps of: cutting a workpiece along two cutting lines with a pair of blades at the same time while moving said pair of blades and said workpiece along the X-axis relatively to one another, said pair of blades being arranged oppositely at a predetermined interval along the Y-axis; after cutting the workpiece along said two cutting lines, moving said pair of blades by a pitch of cutting lines, thereby cutting the workpiece along the next two cutting lines at the same time; and repeating the cutting such that the workpiece is cut along the cutting lines sequentially.
To achieve the above-mentioned object, the present invention is directed to a workpiece cutting method in a dicing machine comprising the steps of: arranging a pair of blades oppositely along the Y-axis, setting an interval between said pair of blades at the total pitches of cutting lines on the workpiece, and moving said pair of blades and the workpiece along the X-axis relatively to one another, thereby cutting the workpiece along two cutting lines at both ends thereof at the same time; after cutting the workpiece along said two cutting lines, moving one blade of said pair of blades along the Y-axis by one pitch toward the other blade, and moving the other blade along the Y-axis by one pitch toward said one blade, thereby cutting the workpiece along the next two cutting lines at the same time; and repeating the cutting such that the workpiece is cut along the cutting lines sequentially.
According to the present invention, two blades are arranged oppositely at a predetermined interval along the Y-axis. The two blades cut the workpiece along two cutting lines at the same time while the two blades and the workpiece are moved along the X-axis relatively to one another. After the workpiece is cut along these two cutting lines, the two blades are moved along the Y-axis by one pitch of the cutting lines so that the workpiece can be cut along the next two cutting lines. This action is repeated to cut the workpiece along the cutting lines continuously. According to the present invention, the oppositely-arranged two blades cut the workpiece, thereby holding the relative movement along the X-axis to a minimum and reducing the cutting time.
According to the present invention, the workpiece is divided into a plurality of cutting areas, and each cutting area is sequentially cut along a plurality of cutting lines. This holds the relative movement along the X-axis to a minimum.
According to the present invention, two blades are arranged oppositely along the Y-axis, and they may be arranged at an interval of total pitches of cutting lines. The two blades and the workpiece are moved along the X-axis relatively to one another, and the two blades cut the workpiece along two cutting lines at both ends thereof at the same time. After the workpiece is cut along these two cutting lines, one of two blades is moved by one pitch along the Y-axis toward the other blade and the other blade is moved by one pitch along the Y-axis toward the one blade, so that the workpiece can be cut along the next two cutting lines. This action is repeated to cut the workpiece along cutting lines continuously. According to the present invention, the two blades are arranged oppositely, and thus, the relative movement along the X-axis is held to a minimum, and the cutting time is reduced.